Honda ST50 Shop Manual page 22

20
""·"
Fla- 29
,
...
,.
Carn Sprocket
cam Chain
8. Measuring the inside diameter of
the
cylinder
Use a cy!indcr pugc and measure the inside
diameter of the cylinder at the top, center and
bottom in both X and Y axes.
Jf the
cylinder
is excessively worn,
ii
should be either rcborcd
or replaced wi1h a new cylinder depending
upon the ex tent of wear (Fig. 27).
mm(iDCh)
S11ndard Value Servitu.blc Llnut
ST
j()
(r
s~::r;~M,
39.,
(I.
539)
s'fl'o-"'==="-l- - -_:_-
cnoK1,
K2,K3
CT70H,
HKI
Note:
47.005-47,0IS
(t.8.506- i.8Sl0)
47.l(l.8S4)
When reborlng the cylinder, It must be re-
bored to o"erslu units of 0.05mm (0.010 in)
to a mu:imum of J.Omm (0.040 in).
The
plston
and piston ring sets are those oYersizes only.
Rff.Sscmbly
Perform the reassembly in
the
reverse order of
disassembly dNCribcd in paae 13 section 5.3,
Follow the procedure below for timing the valves.
Position the key of
the
left crankshaft so that
it
is poin1ing toward the cyli nder head, and posi1ion
the
cam so that 1hc "O" marking on the cam sp-
rockc1 is at the top (Flg.28).
Note:
I. When
lnslalllng the cylinder head, tbe cam
sprocket mllSt
bt contained within
the cyli-
nder head (Fig. 29.
Do not forget
10
lruitall the respectl•e gaskets,
dowel pins and rings.
3.
The
position of the cylinder head nuts bi
(J), ~. and (3) for the blind nut, and @ for
the pllin nul. Do not omll the waling washer
on
tbe
®
position
(Fig. 30).
4. When torquing down the cylinder head,
ligblen Che DUii uniformly In
a diagonal
sequence as
shown In
Fig. 30 and torque to
Che
final spedlkd torque ftlue of 90-120
kg-cm (6.S-9 ft-lb).